The long-term objective for this project is to understand the mechanisms involved in regulating coordinate gene expression during cellular proliferation. Interleukin 2 stimulated T lymphocytes will be used as a model to study cell cycle progression. Specifically, the expression of cyclin, a proliferation associated gene, during initial IL2-stimulated G1 activation, active pro- liferation, and return to quiescence will be determined as will the factors responsible for regulating cyclin expression. In addition, other cell cycle dependent genes that regulated coordinately with cyclin will be isolated. Molecular cytological techniques will be used to carry out these studies. An understanding of the regulation of genes that are required for normal cellular proliferation should give us valuable insight into the pathobiology of neoplasia.